Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W74/00—Wireless channel access
  • H04W74/08—Non-scheduled access, e.g. ALOHA
  • H04W74/0808—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/20—Control channels or signalling for resource management
  • H04W72/23—Control channels or signalling for resource management in the downlink direction of a wireless link, i.e. towards a terminal
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/50—Allocation or scheduling criteria for wireless resources
  • H04W72/54—Allocation or scheduling criteria for wireless resources based on quality criteria
  • H04W72/541—Allocation or scheduling criteria for wireless resources based on quality criteria using the level of interference

Definitions

• the present invention relates to a communication system, and more particularly, to a method for sharing a wireless channel resource in a communication system.
• Bluetooth and wireless personal area network (WPAN) technologies have been developed which can transmit and receive audio and video data between devices by forming a wireless network between a relatively small number of digital devices in a limited space such as a home or a small-size office.
• the WPAN may be used to exchange information between a relatively small number of digital devices that are relatively close to one another and enables the digital devices to communicate with each other at low power and low costs. If communication is performed using wireless technologies, it is possible to remove lines such as cables used to connect the devices. Moreover, data information can be directly exchanged between the devices through wireless network communication between the devices.
• TDMA time division multiple access
• QoS quality of service
• An object of the present invention devised to solve the problem lies in providing a method for sharing a channel in a communication system. Another object of the present invention is to provide a method for stopping communication when interference is detected during channel- shared communication.
• a method for sharing a channel in a communication system including a user device comprises receiving information about a first channel time reserved by other user devices from a coordinator, and performing data communication in a second channel time reserved for other user devices to use if a result of performing scanning in the first channel time indicates that no interference occurs, wherein the communication system performs communication using beam signals which are directional.
• the beam signals may be mmWave signals.
• the method may further include repeatedly performing scanning in the first channel time while performing the data communication.
• the method may further include terminating the data communication upon detecting data transmission and reception of other user devices while performing the data communication .
• the method may further include terminating the data communication upon receiving the signal indicating that interference has occurred from at least one of other user devices and the communication system while performing the data communication.
• the channel sharing method communication can be performed even at a reserved channel time. Moreover, a limited wireless resource can be efficiently used by sharing a channel. When the channel sharing method is applied to communication having a strong directional characteristic, effect thereof can be further increased.
• FIG. 1 is a view explaining an exemplary WVAN comprised of a plurality of user devices
• FIG. 2 is a view explaining an exemplary superframe structure used in a WVAN
• FIG. 3 is a view explaining a channel access method when no channel time is reserved in a superframe
• FIG. 4 is a view explaining a channel sharing method when a reserved channel time is present in a superframe according to an exemplary embodiment of the present invention
• FIG. 5 (a) and 5 (b) are views explaining a channel sharing method according to an exemplary embodiment of the present invention.
• FIGS. 6 (a) and 6 (b) are views explaining a method for terminating communication when an interference signal is subsequently detected according to an exemplary embodiment of the present invention.
• FIGS. 7 (a) , 7 (b) , and 7(c) are views explaining a method for terminating communication when an interference signal is subsequently detected according to another exemplary embodiment of the present invention.
• a user device may be modified to a device, a user equipment, a station, etc.
• a coordinator may be modified to a control device, a controller, a coordinating device, a coordinating (or control) station, a piconet coordinator (PNC), etc.
• a data packet may refer to transmitted and received information, such as a message, traffic, a video/audio (A/V) data packet, and a control data packet, and is not limited to a specific data packet.
• Devices performing communication in a communication system include all digital devices, such as a computer, a personal digital assistant (PDA) , a notebook computer, a digital TV, a camcoder, a digital camera, a printer, a microphone, a speaker, a headset, a barcode reader, a display, a cellular phone, etc.
• PDA personal digital assistant
• WVAN wireless video area network
• WiHD wireless HD
• FIG. 1 is a view explaining an exemplary WVAN comprised of a plurality of user devices.
• WVAN is a network constructed to exchange data between user devices located in a certain space.
• WVAN is comprised of two or more user devices 10 to 14 and one of the user devices operates as a coordinator 10.
• the coordinator 10 in constructing a wireless network between user devices, is a device which allocates a wireless resource and performs a scheduling function in order to share the wireless resource without collision between a plurality of user devices.
• the coordinator 10 allocates a wireless resource and performs scheduling to periodically transmit a message including scheduling information to the user devices.
• the message is referred to as a beacon.
• the coordinator can transmit and receive, as a usual user device, data through at least one channel as well as allocates resources so that the user devices constituting the network can perform communication.
• the coordinator also can implement clock synchronization, network association, bandwidth resource maintenance, and the like.
• WVAN supports two physical layers, a high-rate physical layer (HRP) and a low-rate physical layer (LRP) .
• HRP is a physical layer supporting a data transmission rate over 1 Gb/s
• LRP is a physical layer supporting a data transmission rate of a few Mb/s.
• HRP is highly directional and is used to transmit an isochronous data stream, asynchronous data, a medium access control (MAC) command, and A/V control data, through unicast connection.
• LRP supports a directional or omni- directional mode and is used to transmit a beacon, asynchronous data, and a MAC command including the beacon, through unicast connection or broadcast.
• An HRP channel and an LRP channel share a frequency band and are discriminated by a time division multiplexing
• GHz at a frequency band of 57 to 66 GHz and LRP uses three channels of a bandwidth of 92 MHz .
• FIG. 2 is a view explaining an exemplary superframe structure used in a WVAN.
• each superframe includes a region in which a beacon 20 is transmitted, a reserved channel time block 22, and an unreserved channel time block 21.
• Each channel time block (CTB) is time-divided into an HRP region in which data is transmitted through an HRP and an LRP region in which data is transmitted through an LRP.
• the beacon 20 is periodically transmitted by a coordinator. An introductory part of every superframe can be discerned through the beacon.
• CSMA carrier sense multiple access
• CSMA which is a listen-before-talk scheme, starts communication when a communicating entity does not exist as a result of determining whether there is a communicating entity through a corresponding resource before starting communication. Since this method can not fully avoid collision, in video transmission for example, in which QoS is important, it is desirable to access a channel by previously allocating time using TDMA whenever connection is made.
• a channel time allocated is limited, if a channel time is reserved by one or more user devices in TDMA-based communication, other user devices can not transmit and receive data during that channel time.
• a method for sharing a channel by one or more user devices according to an exemplary embodiment of the present invention will be described.
• a plurality of user devices can share the same channel time.
• beam signals are highly directional as in mm-wave transmission, if directions of the beam signals differ, a channel can be used without collision even though user devices simultaneously access the channel.
• a desired multiple access method may differ according to a service provided by a user device or a characteristic of transmitted or received data.
• TDMA which can ensure less interference and less collision is used to reserve and utilize a channel time.
• CSMA is used to access a channel. Even in this case, however, this embodiment permits an opportunity to access a channel time which has already been allocated by TDMA.
• FIG. 3 is a view explaining a channel access method when no channel time is reserved in a superframe .
• a user device can obtain scheduling information about a corresponding superframe through a beacon received from a coordinator.
• the scheduling information includes information about a channel time reserved by user devices which reserve a partial channel time according to TDMA. If the scheduling information indicates that a channel time is not reserved within a corresponding superframe, the user device can transmit and receive data by accessing the whole channel time using CSMA as illustrated in FIG. 3.
• FIG. 4 is a view explaining a channel sharing method when a reserved channel time is present in a superframe according to an exemplary embodiment of the present invention. If scheduling information indicates that a reserved channel time is present within a corresponding superframe, the user device performs communication using different access methods with respect to a reserved channel time and an unreserved channel time. A general CSMA method is used to access the unreserved channel time as in FIG. 4 and a channel sharing method according to the present invention is used to access the reserved channel time, thereby transmitting and receiving data.
• FIGS. 5 (a) and 5 (b) are views explaining a channel sharing method according to an exemplary embodiment of the present invention.
• a method for sharing a channel by accessing a channel time reserved by another user device is provided.
• user devices C and D can confirm a reserved channel time through scheduling information and desire to transmit and receive data by accessing even a channel time reserved by other user devices A and B, the user devices C and D scan the reserved channel time during a specific time before determining use of the reserved channel time .
• the user devices C and D When the user devices C and D which have not reserved the channel time as illustrated in FIG. 5 (a) communicate through the reserved channel time, the user devices C and D may further transmit identifier (ID) information which can identify a user device while transmitting data. If data including ID information is transmitted and received, the ID information can be used when the user devices A and B which detect interference during communication transmit a communication stop request signal to at least one of the user devices C and D which have caused the interference .
• ID identifier
• each user device When communication is performed two or more times through one channel time according to the above-described channel sharing method, it is desirable to implement repeated scanning. Since the location of each user device is variable and communication environments also have various parameters, even though a signal is not detected by other communication entities at the moment when performing scanning for connection, interference or collision between data may occur subsequently during communication due to other communication entities. It is desirable that the entities performing such repeated scanning are user devices which access a corresponding channel time by performing scanning without reserving the channel time.
• FIGS. 6 (a) and 6 (b) are views explaining a method for terminating communication when an interference signal is subsequently detected according to an exemplary embodiment of the present invention.
• FIGS. 7 (a) , 7 (b) , and 7(c) are views explaining a method for terminating communication when an interference signal is subsequently detected according to another exemplary embodiment of the present invention.
• User devices A and B which reserve a channel time and perform communication during the reserved channel time also can detect, during communication, interference caused by other user devices C and D. If the user devices C and D transmit and receive data including ID information, the user devices A and B can confirm that which of the user devices C and D causes the interference.
• the user devices A and B which have detected interference during communication can transmit a communication stop request signal to at least one of the user devices C and D which have caused the interference.
• the user devices A and B which have detected the interference during communication can report the occurrence of interference to a coordinator of a communication system.
• the coordinator which has received the report transmits a communication stop request signal to at least one of the user devices C and D which have caused the interference .
• the user devices C and D stop communication. Further, in FIG. 6 and FIG.
• the user devices for example, A and B which perform communication sensitive to QoS may use a channel time by reservation
• the user devices, for example, C and D which are less sensitive to QoS may use a reserved channel time through scanning even in a channel time reserved by other user devices, thereby increasing an effect of the user devices.
• the embodiments of the present invention may be achieved by one or more application specific integrated circuits (ASICs) , digital signal processors (DSPs) , digital signal processing devices (DSPDs) , programmable logic devices (PLDs) , field programmable gate arrays (FPGAs) , processors, controllers, microcontrollers, microprocessors, etc.
• ASICs application specific integrated circuits
• DSPs digital signal processors
• DSPDs digital signal processing devices
• PLDs programmable logic devices
• FPGAs field programmable gate arrays
• processors controllers, microcontrollers, microprocessors, etc.
• a software code may be stored in a memory unit and driven by a processor.
• the memory unit is located at the interior or exterior of the processor and may transmit data to and receive data from the processor via various known means.
• the present invention provides a method for sharing a channel in a communication system. Especially, the present invention is applicable to wireless devices using highly directional beams such raraWave .

Landscapes

• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Quality & Reliability (AREA)
• Mobile Radio Communication Systems (AREA)
• Time-Division Multiplex Systems (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=40549738

Family Applications (1)

Country Status (6)

Families Citing this family (10)

Family Cites Families (17)

• 2007
  • 2007-10-08 KR KR1020070101029A patent/KR101459756B1/ko not_active Expired - Fee Related
• 2008
  • 2008-10-08 WO PCT/KR2008/005902 patent/WO2009048257A2/en not_active Ceased
  • 2008-10-08 US US12/681,369 patent/US8385254B2/en not_active Expired - Fee Related
  • 2008-10-08 JP JP2010528800A patent/JP5323847B2/ja not_active Expired - Fee Related
  • 2008-10-08 CN CN200880110754.5A patent/CN101821967B/zh not_active Expired - Fee Related
  • 2008-10-08 EP EP08837847.6A patent/EP2198537A4/de not_active Withdrawn

Also Published As

Similar Documents

Legal Events